Light emitting diode (LED) lighting technology is rapidly developing to replace traditional incandescent and fluorescent lighting. LED tube lamps are mercury-free in comparison with fluorescent tube lamps that need to be filled with inert gas and mercury. Thus, it is not surprising that LED tube lamps are becoming a highly desirable illumination option among different available lighting systems used in homes and workplaces, which used to be dominated by traditional lighting options such as compact fluorescent light bulbs (CFLs) and fluorescent tube lamps. Benefits of LED tube lamps include improved durability and longevity and far less energy consumption; therefore, when taking into account all factors, they are typically considered a cost effective lighting option.
Typical LED tube lamps each have a variety of LED lamp components and driving circuits. The LED lamp components include LED chip-packaging elements, light diffusion elements, high efficient heat dissipating elements, light reflective boards and light diffusing boards. Heat generated by the LED lamp components and the driving elements is considerable and mainly dominates the illumination intensity such that the heat dissipation should be properly disposed to avoid rapid decrease of the luminance and the lifetime of the LED lamps. Problems including power loss, rapid light decay, and short lifetime due to poor heat dissipation tend to be key factors in consideration of improving the performance of the LED illuminating system. It is therefore one of the important issues to improve on the heat dissipation aspects of the LED products. Nowadays, most LED tube lamps use plastic tubes and metallic elements to dissipate heat from the LEDs. The metallic elements disposed to dissipate heat from the LEDs may be made of aluminum.
Current ways of using LED lamps such as LED tube lamps to replace traditional lighting devices (referring mainly to fluorescent lamps) include using a ballast-compatible LED tube lamp. Typically on the basis that there is no need to change the electrical or conductive wirings in the traditional lamps, an LED tube lamp can be used to directly replace e.g. a fluorescent lamp. But an LED is a nonlinear component with significantly different characteristics from a fluorescent lamp. Therefore, using an LED tube lamp with an electronic ballast impacts the resonant circuit design of the electronic ballast, causing a compatibility problem.
Further, the driving of an LED uses a DC driving signal, but the driving signal for a fluorescent lamp is a low-frequency, low-voltage AC signal as provided by an AC powerline, a high-frequency, high-voltage AC signal provided by a ballast, or even a DC signal provided by a battery for emergency lighting applications. Since the voltages and frequency spectrums of these types of signals differ significantly, simply performing a rectification to produce the required DC driving signal in an LED tube lamp is not competent at achieving the LED tube lamp's compatibility with traditional driving systems of a fluorescent lamp.
In addition, the LED tube lamp may be provided with power via two ends of the lamp and a user can be easily electrically shocked when one end of the lamp is already inserted into a terminal of a power supply while the other end is held by the user to reach the other terminal of the power supply. For example, when the user is not properly installing or has not properly or completely installed a common LED tube lamp onto a lamp holder or socket, the user may be likely to be electrically shocked by an accidental current through the lamp's internal circuitry and the body of the user touching the lamp or holder. Common or conventional LED tube lamps do not include a device to prevent the accidental electrical shock on the user who is installing the tube lamp.
As a result, currently applied techniques often fall short when attempting to address the above-mentioned worse heat conduction, poor heat dissipation, heat deformation, electric shock, weak electrical connection, smaller driving bandwidth, and variable factor in manufacture defects.